What antibiotics are used for farm animals?

August 14, 2017

Thousands of recent online searches center around questions about what antibiotics are used on the farm and why. These are great questions and my goal is to provide honest answers.

In my previous blog, “3 reasons why antibiotics are given to farm animals,” I answered the “why” question with three key points related to preventing animal suffering, contributing to a healthy food supply and ensuring sustainability. The simple answer would be that responsible antibiotic use is the ethical thing to do.

So, let’s tackle the question about which antibiotics are used to treat farm animals. According to a 2015 Food and Drug Administration report, there are 18 antibiotic drug classes approved for use in food-producing animals which were actively marketed in 2015 (the most recent data). Some of the names you may recognize, such as penicillin and tetracyclines, but most of them I recognize only because I’m a veterinarian.

More important than their names is the way they are used and the intersection between human and animal health. Some antibiotics are approved for use in animals, others in people, and still others in both animals and people (also called shared class antibiotics). Shared class antibiotics may either be the exact same compound or be different compounds, but they work in a similar fashion as a drug used in human medicine.

The U.S. Food and Drug Administration (FDA) ranked antibiotics based on their importance to human medicine. Most of the antibiotics used in livestock that are also used in humans are on this list, and certain restrictions apply to their use in agriculture. Animal health companies, farmers, veterinarians and the FDA came together and agreed to the limitations in an effort to combat antibiotic resistance.

An important point here: The most commonly used drug classes in humans and animals are very different. According to the American Meat Institute’s “The Facts About Antibiotics in Livestock & Poultry Production”:

  • Approximately 70 percent of the volume of antibiotics used in animals are ionophores and tetracyclines. Ionophores aren’t used in human medicine, and tetracyclines, although listed as an antibiotic important to human medicine, only have a 4 percent human usage rate.
  • Conversely, approximately 73 percent of the volume of antibiotics used in humans are from three classes: penicillin, cephalosporin and sulfa. In animals, those three antibiotic classes account for about 10 percent of use.

The Centers for Disease Control and Prevention identified the most concerning public health threats from antibiotic-resistant bacteria, and none of the most urgent threats are related to farm animals. On the broader CDC list, which includes less urgent threats, only two of 18 involve bacteria associated with farm animals.

So where does all this leave us?

  1. Antibiotics are one of many tools veterinarians and farmers rely upon to protect animal health.
  1. Antibiotic resistance is a serious issue and both human and animal health experts are working to address it.
  1. The most common classes of antibiotics used in livestock aren’t used much in people.
  1. Antibiotics must be used responsibly – in human and animal medicine – to minimize antibiotic resistance.
  1. There are benefits – for people, animals and the planet – from the responsible use of antibiotics.

I welcome your thoughts and questions. Please feel free to send me an email at AskDrDorman@pahc.com or call me at 844-288-3623. You can also browse our Resource Library to learn more about this important topic.